Question 111542
To write the equations, realize that y will be the amount of money paid and x will be the number of rides.
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Option 1: {{{y=25}}}, because whether you go on 0 or 100 rides, the cost is the same.
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Option 2: {{{y=3x/4+5}}}, because .75 = 3/4 and you have the initial $5 cost.
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Option 3: {{{y=5x/4}}}, 1.25 = 5/4
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Now, evaluating each option for 17 rides:
{{{y=25}}}
{{{y=(3/4)(17)+5=17.75}}} (I used a calculator)
{{{y=(5/4)(17)=21.25}}}
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Option 2 is the cheapest.
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You should get extra credit for this next part:
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{{{graph(400,400,-10,30,-10,30,25,3x/4+5,5x/4)}}}
The horizontal line is option 1, the green line is option 2, and the blue line is option 3.
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Option 3 is a good deal if you aren't going on more than 9 rides.  If you go on 10 rides, Option 3 and Option 2 cost the same.
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If you are going to ride 11 times or more up to 26 times, then Option 2 is the best deal.
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Option 1 isn't a good deal unless you are going to go on 27 rides or more.